GO FOR IT! Roy Oswalt wants out of Houston -- and the Mets should go all-out to deal for the star right-hander while there's still time to turn around the season and become a contender. Getty Images

Nearly four hours before last night’s game, Oliver Perez was in right field at Citi Field working on his conditioning drills. He should have been working in Allentown, where the Buffalo Bisons were playing the Lehigh Valley IronPigs.

Mike Pelfrey and Francisco Rodriguez pitched the Mets to a 5-3 victory over the Yankees last night in the second game of the Subway Series. The Mets remain last in the NL East with a 21-23 record, but only six games back of the first-place Phillies.

There is a way to turn around this season, and it’s not by firing somebody. It’s by hiring somebody.

The Mets need to go out and do whatever it takes to bring Roy Oswalt to Citi Field.

Adding a quality veteran pitcher would give a boost to the entire team. Oswalt, the Astros’ star right-hander, said he wants to go to a contender.

For now, the Mets don’t fall into that category.

But Oswalt could make it so.

It’s much too early to write off the Mets, even though they have struggled. And here’s the most important bit of information.

“He would come here,” one Met who knows Oswalt well told me. “He knows he would make a huge difference for us, and he knows some of the guys. He would be comfortable here. He’s still a great pitcher.”

The question is, will Mets management step up to the plate and take on Oswalt’s salary? This is a staff that needs help, and Oswalt would give that help immediately.

Pitching in spacious Citi Field is a delight. Oswalt, 32, is dying to get out of Houston. He’s struggling for run support, and that might be a problem here, but it still is better than pitching for the Astros, who dropped to 15-28. Only the 14-30 Orioles have a worse record.

Bringing in Oswalt would be about a $29 million commitment for the next two years, and there is a $16 million option for 2012 or a $2 million buyout. Before the season started, the Mets said they had $10 million to add to payroll during the season. This would be more, but the upside would be worth it.

And look at the money they are wasting on pitching anyway, starting with the $36 million they committed to giving Perez last year.

Bottom line: If the Mets step up to the plate, this is a trade that can be made because they have enough young talent to make a deal and the Astros have no reason to keep Oswalt.

Houston is dead last in the majors in batting average (.228), dead last in home runs (21) and dead last in runs scored with 124. There’s the Triple Crown — that’s the Triple Frown.

The Astros’ woes are much worse than the Mets’ problems.

The Mets have gone down this road before, nearly acquiring Oswalt in 2006. Imagine how that would have changed things.

Willie Randolph might still be managing the Mets, and collapses probably would not have occurred. The Mets missed that opportunity. They can’t afford to miss this opportunity.

The way they are currently constructed, they have no shot at making the postseason. Oswalt doesn’t guarantee a turnaround. Nothing is ever etched in stone with the Mets, but considering what is available, he is by far the best option they have of overcoming previous mistakes like signing Perez long term.

Oswalt is a difference-maker, and the Mets could use someone who can make a difference.